Assembly apparatus



Sept. 23, 1958 H. D. scHNiTzlUs 2,853,118

ASSEMBLY APPARATUS Filed Feb. 9, 1956 4 Sheets-Sheet 1 H. D. scHNlTzlUsASSEMBLY APPARATUS sept. 23, 195s 4 Sheets-Sheeil 2 Filed Feb. 9, 1956-'Wml Sept. 23, 1958 H. D. scHNlTzlUs ASSEMBLY APPARATUS Filed Feb. 9,195e 4 Sheets-Sheer. 5

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ASSEMBLY APPARATUS Filed Feb. 9, 1956 4 Sheets-Sheet 4 5%' ffm nitedStates Patent C) ASSEMBLY APPARATUS Homer D. Schuitzius, Indianapolis,Ind., assignor to The Richardson Company, Melrose Park, Ill., acorporation of Ohio Application February 9, 1956, Serial No. 564,416

17 Claims. (Cl. 154-1) This invention relates to an apparatus forassembling component parts to form a composite body. More particularlythe invention is directed to utilizing the heat developed by friction tosoften a given area of one component part made from a thermoplasticmaterial whereby the softened area of the part may be deformed about itscomplementary part to thereby interlock the two component parts to forma unitary product.

In describing the invention reference will be made to the drawingswherein;

Figure l is a partial front perspective view showing the relationship ofthe chuck and roller assembly forming a part of the apparatus.

Figure 2 is a schematic view in elevation, partly in section, of thecontrol and power train mechanism.

Figure 3 is a front elevation view, partly in section, of the chuck androller assembly while Figures 3a and 3b, associated with Figure 3, areelevational views, in cross section, of vent caps in initial and finalstages of assembly respectively.

Figure 4 is an elevation view, partly in section, of the cam assemblycontrolling the movement of the chuck.

Figure 5 is a further elevational view, partly in section, of the chuckcam assembly.

Figure 6 is a plan view of an assembled battery vent well plug.

Figure 7 is a plan view of the slide mechanisms used to perform theinitial assembly operation.

Figure 8 is a side elevational view, partly in section, showing therelationship of the initial assembly mechanism and the chuck and rollerassembly.

Figure 9 is a partial view of a modication of the means employed tocreate frictional heat and unite the component parts of the compositebody.

In order to describe and explain the invention, reference will be madeto the formation of battery vent plugs. However, it will be appreciatedthat the process and apparatus described may be employed to form similarproducts from two complementary component parts.

In the usual electric storage battery there are provided lling wells foreach cell through which may be poured the electrolyte for the cells.After filling each cell with electrolyte, the lling wells are thenclosed with a hollow vent plug, usually secured within the filling wellby means of threads. Such a vent plug is normally cylindrical-like inshape and is provided with openings in both its top and bottom. Thesevertically spaced vent plug openings obstruct the discharge ofelectrolyte while permitting the egress of gases which are evolved fromthe cell.

Vent plugs as described above are usually made of plastic material by amolding operation and, because of their structure, are initially formedin two parts, namely a base portion and a cap portion, which aresubsequently united to form the complete vent plug. The vent plugsassembled in accordance with the teachings of the present invention aremolded from polystyrene.

In order to more fully describe such a plug, reference cell.

ice

is made toV Figure 3a of the drawings wherein there is shown a-cylindrical type base B provided with external threads a on the lowerportion thereof. In the bottom of the base there is a small opening x aswell as an upstanding bale f, referred to hereinafter. Further, the baseis provided with an integral cap support, which in one embodiment, maybe represented by ledge b extending around its inner periphery, theupwardly extending portion of the sides of the base beyond said ledgebeing designated by the letter e. The cap C which is to be united withthe base B is shown as having a transverse opening y in the centerthereof and a peripherial lip d which will permit the cap to besupported by ledge b of the base B.

The exemplary embodiment of the present invention is directed to unitingthe cap C with the base B by turning upper edge e of the base over thelip d of the cap such that a permanent unitary structure is formed, asis shown in Figure 3b, and the two parts of the plug are lockedtogether, the lip d of the cap being held between ledge b and turnedover edge e.

The assembled vent plug when inserted into the filling well of a batterywill serve to prevent splashing of electrolyte out of the vent well butwill permit, by means of openings x and y, the egress of any gasesformed in the There is some possibility that electrolyte might find itsway up through opening x in the bottom of the vent plug, however, byreason of the presence of the bafe f and the offset between the openingsx and y, the electrolyte has no direct passage to the exterior and,hence, is normally 4entrapped in the plug interior. A plan view of anassembled vent plug is shown in Figure 6.

The apparatus and process for uniting the two parts of the vent plugwill be now described in more detail.

Chuck and roller assembly In describing this portion of the apparatusreference, in general, will be made to Figures l and 3. In brief, theapparatus employed consists of a chuck which receives the base and capin an initially assembled condition, with cap C resting on ledge b ofbase B, and which, under appropriate sequence of steps, forces theassembled base and cap against an external freely movable surface whilerapidly rotating the assembly, to thereby turn the edge e over the lip dof the cap. The base, at least, is formed of thermoplastic materialwhereby a given portion of the base, upon being rapidly rotated againstthe aforementioned surface, will be subjected to frictional engagementwith the same thereby creating heat. The freely movable surface issoconstructed that as the predetermined portion of the plastic base isheated by means of the friction created it will be softened andautomatically deformed about the periphery of the cap.

In Figures 3, 3a and 3b there are shown the three stages for assemblingthe vent plug, the assembly stages progressing from left to right.

Referring now more particularly to Figures 1 and 3, there is shown abase plate 1 upon which are supported two freely rotatable rollers 2.The rollers are provided with concave peripheral surfaces 3 and are eachattached to a shaft 4 and 5 respectively, which in turn are journaled insupport members 6 and 7 attached to the base plate 1.

Disposed in an opening in the base immediately below the rollers is arotatable and longitudinally movable chuck 9 secured to a shaft lil, thelatter extending downwardly through and being journaled in housing H.The housing H contains appropriate control mechanism and a power train,referred to hereinafter. The face of the chuck is provided with a cavity11 into which will be received the bottom threaded portion of the baseB.

Extending upwardly into the cavity 11 is an ejector pin 12 which isbiased by spring 13. Also extending into cavity 11 are two driving pins14 and 15 which are likewise biased by springs 16 and 17 respectively.When the base B is fixed in the cavity 11 of the chuck, the ejector willbe depressed and one of the driving pins 14 or 15 will be engaged withand extend into opening x in the bottom of base B, thereby locking thebase with the chuck for simultaneous rotation.

In order to hold the initially assembled parts C and B of the vent plugtogether during the preliminary period when the assembly is beingpositioned over the chuck and engaged therewith prior to softening andturning the edges e, there is provided a holding pad 20 which isresiliently mounted in an overhead support 21, the pad being biased by aspring 22.

When the initially assembled elements C and B are first positioned overthe chuck, by means of slide mechanisms hereinafter described, a stopmember 24 is employed to prevent the assembly from traveling beyond itsdesired position immediately over the chuck. This stop member 24consists of a flexible spring reciprocally operable in a tube 25 andcontrolled in timed sequence by pneumatic means through hose 26.

After the component parts of the vent plug are united in the mannerpreviously indicated, the vent plug is ejected from the chuck and guidemember 27 is provided which, in general, controls the path that thecompleted assembly will take immediately after being removed from thechuck.

Slide and plunger mechanism As previously indicated, it is necessarythat the cap and base be initially assembled before being disposed inthe chuck for permanent uniting. In accordance with the presentinvention, means are provided for so assemblying the elements C and Band subsequently transposing the assembly to the chuck `for the naluniting operation. The mechanism for accomplishing -the foregoing isbest shown in Figures 7 and 8 o f the drawing. The base and cap areindividually supplied from hoppers not shown to the initial assemblystation by means of chutes 30 and 31. In order to transfer therespective elements from their chutes there are provided reciprocatingslides which remove the bases and caps from their chutes in appropriatesequence and carry them to the initial assembly point or station. Thenumeral 32 designates the slide which will remove the base element Bfrom its chute 30, when in the retracted position shown by the dottedlines. Slide 32 carries the base B forward to a point where it ispositioned upon a spring biased supporting pad 34, the latter beingdisposed in an opening in the base plate 1. In a similar manner slide33, when in the retracted position shown by the dotted lines, willremove a cap element and carry it forward until it is positioned overits complementary base and vertically spaced therefrom. The position ofthe two elements B and C immediately prior to the initial assembly isbest shown in Figure 8. Upon reaching this stage, wherein the cap ispositioned just above the base, a plunger 35 is caused to movedownwardly which forces the cap into the upper opening of the base so asto rest upon and be supported by the ledge b of the base.

Once the initial assembly of the base and cap has been completed in theaforementioned manner, the slides 32 and 33 are retracted to pick upadditional elements for assembly and a cross slide 36 is caused to movetransversely, as from left to right in Figure 7, until it has transposedthe initial assembly over the chuck 9 and against the stop 24, which atthe time is automatically extended outwardly into the forward path ofthe assembly just beyond the chuck. An extension 37 of slide 36 servesto limit the travel of the base B when it is moved by its slide 32 andthus aids in properly locating the base on supporting pad 34.

The movements of the slides 32, 33 and 36 and the movement of theplunger 35 are all controlled so as to operate in appropriate sequenceby means of mechanisms contained in the housing H and describedimmediately hereinbelow.

Control and power train mechanism As previously indicated, the chuck 9has its associated shaft 10 extending into and journaled in housing Hwhere it is connected with a power supply and where its movement, bothreciprocally and rotatably, is controlled in the manner desired by meansof suitable gearing and cams. In order to describe more fully thisportion of the apparatus employed in the present invention, referenceswill be made to Figures 2, 4 and 5, wherein there is shown the housing Hhaving the shaft 10 of the chuck extending therethrough. To transmitpower to the chuck there is provided a drive shaft 40 connected to asuitable source of power by means of a chain and sprocket indicatedgenerally by the numeral 41. One end of the power shaft is provided witha beveled gear 42 which is engaged with a corresponding beveled gear 43secured to the shaft 10. Beveled gear 43, while secured to shaft 10, isso connected thereto as to permit the latter to move longitudinallythrough its center. Rotation of drive shaft 40 will, accordingly, causerotation of shaft 10 and, hence, chuck 9, the speed of rotation of thelatter being determined by the gear ratio.

Also secured to drive shaft 40 is a power transmission link 44 fortransmitting power to cam shaft 45. Cam shaft 45 has secured thereto achuck cam 46. This cam is provided with a varying periphery, as measuredfrom its center, which, as hereinafter described, will impart to therotating chuck a predetermined reciprocal movement, and thus determinethe extent and duration of the contact of the initially assembled ventplug held by the chuck with the rotatable surface or rollers 2.

Means are also provided, associated with the lower end of shaft 10, foradjusting the relationship between cam 45 and shaft 10, whereby themaximum or minimum reciprocal movement of the shaft 10 and hence chuck 9may be controlled. Thus, the lower end of shaft 10 is journaled in andsecured to a floating support 48 which is attached to a projection ofthe housing H by means of bolts 49 and 50 but adapted to move freelythereon. Disposed around the bolts are springs 51 and 52 respectively,which keep member 48 biased in a downwards position. Depending frommember 48 and forming an integral part thereof is a bracket 53comprising two laterally spaced arms, each of which is provided with avertical slot 54 and 55. Disposed in the slots is a. transverse axle 56upon which is journaled a roller 57. The position of the axle 56 in theslots 54 and 55 may be varied by adjustment of locking screws 58. Roller57 is always maintained in contact with the peripheral surface of thecam 46. However, by appropriate adjustment of the locking screws 58, itwill be seen that the position of the axle 56 within slots 54 and 55 maybe changed and thus the maximum or minimum vertical travel of the chuck9 varied. In order to compensate for wear or make other adjustments asmay be required, provision is also made for adjustment of cam 46 withrespect to its position on shaft 45 by means of bolts 59 disposed inslots extending through the cam and engaged with a backup plate asshown.

An arrangement as described above permits a reciprocal movement to beimparted to the chuck 9 while the latter is being rotated.

Also secured to shaft 45 are a number of other cams 61, 62, 63, and 64,which are, in turn, engageable with an equal number of contact elements65, 66, 67 and 63 respectively. These contact elements contro-1, inappropriate sequence, the operation of the initial assembly mechanism,transfer of the assembly to the chuck and ejection of the assembled plugfrom the chuck. Thus,

assente for example, cam 61 can be designated as controlling the baseloading slide, cam 62 as controlling the cap loading slide, cam 63 ascontrolling the cross slide and cam 64 as controlling the plunger 35,previously referred to and shown in Figure 8. It will be understood thatthe mechanisms associated with the contact elements which, in turn,control the aforementioned operations can be any well known means and,hence, the particular arrangement or system used forms no part of thepresent invention and, accordingly, is not shown in the drawings orfurther described.

For a more detailed explanation of the effect of cam 46 on the movementof shaft 10 and thus the movement of the chuck 9, reference is made toFigure 4 wherein there is shown an enlarged View of cam 46 positioned onshaft 45 and in contact with roller 57. Those portions of cam 46 whichserve to control the reciprocal movement of the chuck are indicated bythe bracketsdisposed about the periphery of the cam, the cam beingrotated counterclockwise. Thus it will be seen, starting at the bottomof the cam, that a portion of the periphery of the cam will permit thechuck to be fully retracted, during which period, the initial assembledcap and base are positioned over the chuck, this particular portion ofthe cam surface being designated as Loading of Assembly. Following lthisinitial operation the chuck engages the assembly as it moves upwardunder the influence of that part of the cam surface designatedEngagement of Chuck with Assembly.

The next area of the cam periphery causes the chuck and the vent plugassembly to move upward forcing the upper edges e of the base of theassembly against the rollers.

The fourth bracket area, counterclockwise, of the cam periphery is afinishing and smoothing operation. The lnal bracket area of the camsurface permits retraction of the chuck whereby the united vent plugassembly is removed from contact with the rollers and is ejected fromthe chuck.

Operation To summarize the operation, it will be seen that the two partsof the vent plug, namely cap C and base B, are initially assembled withthe cap lip d resting on the ledge b of the base B, following which theupper edge e of the base B is forced or turned over the lip d of the capto form a mechanical joint and thus lock the two parts of the vent pluginto a permanent unit.

Taking the operation from the beginning, base loading slide 32 removesone base unit from chute 30 and conveys it to an initial assemblystation in a predetermined position over the resiliently supported pad34. Simultaneously with the positioning of the base unit, the caploading slide removes one cap unit from chute 31 and conveys it to theinitial assembly station in a position immediately over the base but invertical spaced relationship thereto. When the cap and base are in theirp predetermined positions, plunger 35 is caused to move downward so asto force cap C into the upper opening of base B whereby the peripherylip d is supported by the inner ledge b of the base. It will beunderstood that when the plunger forces the cap down into the base thatthe supporting pad 34 being resiliently disposed under the base willabsorb a part of the force of the plunger and thus prevent anydistortion of either the cap or the base in the initial assemblyoperation.

Following this initial assembly operation, or more or lesssimultaneously with the movement of the plunger 35, slides 32 and 33 areretracted to the dotted positions shown in Figure 7, in order to permitthem to pick up other base and cap units respectively and also to permitthe cross slide member to move the initially assembled cap and base tothe second or nal assembly station over the chuck. Thus, upon retractionof the slides 32 and 33, cross slide 36 is caused to travel from left toright, as viewed in Figure 7, moving the assembly over chuck 9.

As the assembly is moved over the chuck under the influence of the crossslide, spring 24 is caused to move outward in front of the path of themoving assembly to thereby assist in preventing it from moving beyondits desired position over the chuck. As the assembly is disposed by thecross slide over the chuck, it is, in effect, caught between theextended spring 24, the holding pad 20 and the ejector pin 12 of theupwardly moving chuck and, hence, is held firmly in position. Once theassembly is caught between the pad 20 and the ejector pin 12, stopspring 24 is retracted. Additionally, the chuck continues to move upwardwith the ejector pin 12 being gradually forced downward as the threadedportion of the base B comes within the cavity 11 of the chuck. Duringthe operation of the chuck it is continuously rotating at apredetermined speed and, hence, the bottom of the base B will contactand slide over the driving pins 14 and 15 until one of the pins engagesand forces itself into opening x in the bottom of the base. Uponengagement of a driving pin in the opening x, the chuck and the base arelocked together. Thus the rotary movement of the chuck is immediatelyimparted to the base and cap assembly. The chuck continues to moveupward until the upper edge e of the base B engages with the `concavesurfaces 3 of the rollers 2, the latter, as previously described, beingfreely rotatable. As the upper edge e is moved against the surface 3 ofthe rollers 2 at a very rapid speed, frictional forces cause heat to becreated in the edge e and thus a softening of the thermoplastic materialfrom which it is formed.

The chuck continues to move upwardly under the influence of the cam 46as the edge e is softened and, hence, causes the edge to be forcedinwardly by reason of the concave surface 3 of the rollers 2. Thus, byreason of forcing the softened edges e inwardly they are caused tooverlap and form around lip d of the cap, thereby locking the cap inposition in the base between the turned over edges e and the ledge b.After the edges e are initially turned over the lip d of the cap C, thechuck continues to rotate the turned over edges in Contact with therollers for a short period to further smooth and form the joint, thusmaking it a finished surface and juncture.

After the smoothing operation, the chuck is retracted to a positionwhereby the assembled unit is below the holding pad 20 and where ejectorpin 12 can force the assembled vent plug out of the chuck. As an aid inejecting the thus assembled vent plug, a blast of air may be employed tomove it out of the chuck and toward a collecting station, the air beingappropriately directed by means of a nozzle, not shown.

As previously indicated, the vertical movement of the chuck and,correspondingly, the movement of the initially assembled vent plug intoengagement with the rollers 2 while rapidly rotating is controlled bymeans of cam 46. Certain adjustments with respect to the cam and itscontrol over the operation `of the chuck can be made when desirable.Thus, due to the fact that the position of the shaft 1t) with respect tothe cam may be varied by the locking screws SS, provision is made forthe assembly of vent plugs having varying longitudinal dimensions.

One apparatus of the type described herein for making battery vent plugsof polystyrene has an operation wherein the chuck is rotated at a speedof 400 R. P. M. and the chuck cam 46 constructed so as to reciprocatethe chuck 40 times per minute, thus forming in effect vent plugs at therate of 40 per minute. This rate has been found not only appropriate forcreating the necessary friction to provide the required heat andaccomplish the desired objective of deforming the edges of the base butalso provides a rate of assembly which enables an inspector toadequately inspect the assembled vent plugs without undue strain.

As indicated in the above description of the invention, two rollers areused to provide surfaces against which the initially assembled vent plugis caused to rotate for purposes of developing friction and hence heatto soften the thermoplastic material. However, it will be appreciatedthat other surfaces of a somewhat similar nature which will perform in alike manner may also be employed. There is shown in Figure 9 an exampleof an alternate structure which may be used. In this figure the numeral70 indicates an appropriate supporting plate disposed above the chuckhaving journaled therein for free rotation a downwardly extendingconcave saucer-like member 71, provided with an inwardly disposedconcave periphery for engagement with the upper edges of a base element.

In operation, using a device of this type, the chuck would force theinitially assembled vent plug upward into engagement with the member 71wherein the upper edge e of the base B would contact the inwardlydisposed concave surface 73 of the member 71, resulting in the creationof friction due to the relative movement and thus cause the edge e to beturned over upon being softened in the same manner as was the case withthe preferred structure using two rollers 2.

As previously indicated, assembly of vent plugs whose component partsare formed from polystyrene has proven entirely practical using themethods and apparatus disclosed. Assembly -of similar products formedfrom like materials which can be softened by the heat of friction andthus deformed is also considered to the within the broad concepts of thepresent invention. Additionally, while I have indicated that freelyrotatable external surfaces are preferably desired, it is possible thatstationary external engaging surfaces or movable external engagingsurfaces having a predetermined drag may be also employed, depending onthe material used, friction forces developed, speed of rotation, etc.

Accordingly, while there has been shown and described certain exemplaryembodiments of the invention it will be understood that variousmodifications may be made, the scope of the invention being limited tothe following claims.

I claim:

1. In an apparatus for permanently joining a cap and a cylindrical-like'open-end thermoplastic base to form a composite unit comprisingseparate sources of supply for said cap and base, collecting membersassociated with each source of supply and adapted for removingindividual cap and base elements from said sources and .carry the sameto an initial assembly station in spaced relationship, a press memberlocated at said station axially aligned with said cap and base andadapted to insert said cap within the open end of said base adjacent anintegral support therein, a transferring member adapted to move saidassembly to a second station for permanently uniting the cap in positionwithin the base, a chuck located at said second station, means to locksaid assembly in saidchuck, a movable member disposed above said chuckhaving a surface adapted to frictionally engage external areas of saidbase surrounding the periphery of said cap, means for rapidly rotatingsaid chuck, means to move said chuck during rotation toward said movablemember to permit frictional engagement of said external areas of thebase with said surface of said movable member, said surface beingdesigned so as to deform that area of the base in contact therewithabout the periphery of said cap when said area becomes softened as aresult of the frictional heat developed, means to retract said chuck andthus said base from contact with said movable surface, means disposedwithin said chuck to assist in ejecting said cornposite assembly fromsaid chuck, and means to coordinate the operation of said collecting andtransferring members with the rotary reciprocating operation of saidchuck whereby the initial assembly of the cap and base, the transfer ofthe assembly to the chuck and the final uniting operation are performedin predetermined sequence.

2. In an apparatus as described in claim l wherein the collectingmembers are longitudinally aligned reciprocating slide elements disposedin vertical spaced relationship.

3. In an apparatus as described in claim 2 wherein said transferringmember is a reciprocating slide element whose operating path istransverse to that of the collecting members.

4. In an apparatus as described in claim 3 wherein a portion of saidtransferring member when in retracted position extends across the pathof the thermoplastic base carried by the base collecting member andserves to limit its travel and thus position the same.

5. In an apparatus as described in claim l wherein said means to locksaid assembly in said chuck comprises a spring biased pin disposed inthe chuck cavity and adapted to removably engage a complementary recessin the base.

6. In an apparatus as described in claim l wherein said movable memberconsists of two oppositely disposed freely rotatable rollers whose axesof rotation are normal to the path of travel of the chuck, each of saidrollers being provided with a concave surface adapted for contact withsaid base.

7. In an apparatus as described in claim 6 including a spring biasedholding pad extending downwardly between said rollers and adapted t-oassist in retaining the cap and base in assembled relationship at thesecond station until said assembly is permanently united.

8. In an apparatus as described in claim l including means for adjustingthe maximum and minimum recipro cal movement of said chuck.

9. In an apparatus as described in claim l including a reciprocatingstop member adapted to be momentarily disposed in front of the path ofsaid transferring member to prevent the base carried by saidtransferring member from moving beyond the receiving point of .thechuck, said stop member being momentarily operated in timed sequencewith the movement of said transferring member.

l0. In an apparatus as described in claim 1 wherein said movable surfaceadapted for frictional engagement with said base is a circular concavesurface disposed in a plane normal to the longitudinal path of saidchuck.

ll. In an apparatus for permanently joining a cap and a cylindrical-likeopen-end thermoplastic base to form a composite unit including arotatable chuck adapted to hold the initial assembly of the cap and basewith the cap disposed within the b ase and resting on an internalsupport integral therewith, means to lock said assembly in said chuck, afreely rotatable member disposed above said chuck having a surfaceadapted to frictionally engage external areas of said base surroundingthe periphery of the cap, means to rotate said chuck, means toreciprocate .said chuck during its rotation axially toward and away fromsaid freely rotatable member to permit engagement of said external areasof the base with said surface for a predetermined period of time tothereby soften said areas of the base under the inuence of thefrictional heat developed, said freely rotatable surface being shaped insuch a manner that upon softening of the areas of the base in contacttherewith said areas under continuing pressure will be deformed aboutthe periphery 4of said cap, and means to eject said composite unit fromsaid member of said chuck upon completion of the assembly operation.

12. In an apparatus as described in claim ll wherein the means to locksaid assembly in said ychuck comprises a spring biased pin disposed inthe chuck cavity adapted to removably engage a complementary recess insaid base.

13. In an apparatus as described in claim l1 wherein said ejecting meansincludes a spring biased member disposed in the cavity of said chuckwhich is depressed by said assembly while held by said chuck.

14. In an apparatus as described in claim 1l wherein said freelyrotatable member comprises two oppositely disposed rollers whose axes ofrotation are normal to the reciprocal path of the chuck, each rollerbeing provided with a concave periphery for frictional engagement withsaid base.

15. In an apparatus as described in claim 11 including means foradjusting the maximum and minimum reciprocal travel of said chuck.

16. In an apparatus for permanently joining a cap and a cylindrical-likeopen-end thermoplastic base to form a composite unit including arotatable chuck adapted to hold the initial assembly of the cap and basewith the cap disposed within the base and resting on an internal supportintegral therewith, means associated with said chuck for locking saidchuck and assembly during rotation, a pair of oppositely disposed freelyrotatable rollers positioned in spaced relationship with respect 4tosaid chuck and provided with peripheral concave surfaces adapted forfrictional engagement with predetermined areas of said base, the axes ofrotation of said rollers being normal to the axis of rotation of saidchuck, means to reciprocate said chuck axially towards and away fromsaid rollers to permit frictional engagement lof said predeterminedareas of the base therewith for a time sucient to allow the heat -offriction to soften said predetermined areas of said base and deform saidareas about the periphery of the cap, and a resilient holding paddisposed between said rollers and adapted to press against said capduring the time said cap and base assembly are retained in said chuck.

17. In an apparatus for permanently joining a cap and a cylindrical-likeopen-end thermoplastic base to form a :y

composite unit comprising holding means adapted to receive and retainthe initial assembly of the cap and base wherein the cap is disposedwithin the base and rests on an internal support integral therewith,means for supplying said holding means with the initially assembled capand base, means to lock said assembly within said holding means, anindependent member disposed in spaced relationship with respect to saidholding means having a surface adapted to frictionally engage externalareas of said base surrounding the periphery of the cap, means forrapidly rotating said holding means, means to reciprocate said holdingmeans during rotation toward and away from -said independent member topermit engagement and disengagement of said external areas of the basewith said surface, said surface being designed so as to deform the areasof the base about the periphery of said cap when said areas becomesoftened as a result of the frictional heat developed, means to ejectthe composite unit from said holding means; and means to coordinatesupplying, rotation and reciprocation of said holding means and ejectionof the composite unit whereby such operations are performed inpredetermined sequence.

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